I was just on the ASP page and they have a electronic RWHP calculator. Using Chi-Town SRT/6 1/4 mile speed of 113 MPH and his vehicle weight, that gives him 383 HP at the rear wheels. Add 20% for loss of efficency in the system, that means his SRT6 is turning almost 460 HP at the crank! That is very impressive. Given that his only improvements are a pulley, CAI and reflashing (about $2,000 worth of mods) this is one very economical HP improvement. You be hard pressed finding this kind of gain for this price in other vehicles.

Thanks Chi-Town SRT/6 for paving the way. I can't wait to get mine on the road. I was going to put it up for the winter but I may just take it out from time to time to blow the carbon out of it!

 

Wow! Something tells me those calculations are off a bit. I have a lot of respect for Chi-Town and his mods, but I'm not ready to believe that he's got 460hp at the crank.

Where is this ASP page you mentioned? I'd like to take a look at it.

 

I appreciate your kind words sir...but if I had to guess i would say i'm pushing 365-375 RWHP and am about 405-415 at the wheels. When I dyno'd the car it weighed in at 3,275 and that is the same as my old C5 Z06. My Z06 ran 12.6@113 and had 365ish to the wheels.

 

If your total weight (car and you) is 3275 then their RWHP is 369. That is about 443 at the crank. Even if DC is lying about the SRT6 HP, not 330 but 349, that is still 94 HP! That is a little over $21/HP. If the SRT6 HP is really 330 (I don't believe that) then your HP increase is .... well, you get the idea!

Normally to gain 94 HP you're talking major mods to an engine. To make this kind of HP in most engines you're talking cams, carbs, etc.

http://www.aspracing.com/frame.htm

 

I just visited that ASP page........what a bunch of f*****g theives! Every pulley they have sells for under 200 bucks. Then you look at the Mercedes pulleys.........$650.00!!!!! WTF

 

Using Chi-Town's best time of 12.2, and a weight of 3275, that means he's got 356.5hp at the rear wheel.

The equation is:

RWHP = Weight / ( Time / 5.825)^3

or you can go backwards with:

Time = 5.825 x cube root of (Weight / RWHP)

Isn't math fun?

 

I would be inclined to believe the first post isn't too far off. Given that the NeedsWings intake bosted it an average of 25 Horsepower at the wheels, I don't think another 50-60 RWHP with the Pulley and ECU is unrealistic. I believe the engineers stated that measrued Drive Train Loss on the SRT-6 is about 16-17%. Calculating a RWHP of 380 then add back the 17% loss and you get about 459 HP at the crank. I calculated my RWHP off my timespils and weight and came up with 290 RWHP, that's roughly the same that we have actually seen them put down on a Dynojet. The math all works out to me.

 

According to my calculator, I'm only getting 429.5hp for Chi-Town at the crank. I dunno where you guys are coming up with the extra 30 horses.

Hey NeverEnough, when I run the numbers on the slip you have posted in your signature, I get a RWHP of 271.1 for your car. Is that close to what it dyno-ed at? (that is using 3270 for the weight - assuming that your car weighs about as much as Chi-Town's)

 

I checked out the drag times web site, and the BEST 1/4 time for a stock SRT-6 is 13.06 (Rob at NeedsWings). Using a stock curb weight of 3240 for the vehicle, that gives a RWHP of 287.5 and a Crank HP of 346.4, which is VERY close to the 349 that the Chrysler engineers stated.

If I use Chi-Town's weight (3275) instead of the listed curb weight of 3240, the numbers are even closer for a stock SRT-6 Coupe at RWHP of 290.6 and Crank HP of 350.1. So I think any small variances can be attributed to the weight of the driver and how much gas they had in the tank.

So I think my calculations are correct for Chi-Town's car. With a time of 12.2, and a weight of 3275, Chi-Town is putting 356.5hp to the road, and assuming a 17% drive train loss, he's getting 429.5hp at the crank.

That's still and increase of approx. 80 crank HP for a relatively small investment. Way to go Chi-Town!

I'd still like to see a dyno on your car Chi-Town. That would shut up all of us speculators.

 

My track weight with me in it was 3476 (I'm Fat). That should make up most of the difference right there.

 

Yeah, NeverEnough, that weight makes a difference. With the weight you mentioned, I get 287.7 for your car. Is that close?

On another subject: does anyone want to speculate on how Chi-Town's car weighs only 35 pounds over the curb weight? Either he's awful skinny, or he's removed a couple parts.

 

287 seems pretty close. I used a more elaborate calculater (desktop Dyno) to come up with 291 HP. It takes into account all the atmospheric conditions, Headwinds (if available) etc.

 

That's the weight that came up on the dyno and that was with a half tank of fuel. I weigh 210. I did have the resonator removed but that thing does not weigh more than 20 lbs.

 

Wikipedia defines Curb Weight as:

Curb (kerb) weight is the total weight of a vehicle with standard equipment, all necessary operating consumables (such as motor oil and coolant), a full tank of fuel, and not loaded with either passengers or cargo.

I would bet that the difference in a half tank of fuel is quite a few pounds. How much does one gallon of gas weigh? A gallon of water is 8 lbs. isn't it?

 

http://robrobinette.com/et.htm
try this link for 1/4 mile times. It is consistent with my track times. I have achieved 12.632 - 12.715 consistently over 8 times to the track. This calculator puts my car @ 12.65. My car is completely stock. The numbers are as follows: humidity 33.5%, temp 52 deg F. I don't know the elevation and I don't have a scanner to get the slips posted.
It calculates my car @ approx 363 flywheel hp, at a weight of 3,200 pounds. Changing pulleys and increasing thrust, and dropping the resonator will add hp. Stating that there is a 20% loss in hp through our drive train I think is an overstatement. That would be true for a normal automatic tranny, for ours I would estimate 15% as being more accurate. As for the HP listed on most sites for the hp of our cars that is definitely an understatement. My track times have proven that already. So based on the numbers he has provided, 440 hp at the flywheel does not seem to be impossible.

leadfoot